Refactor to put SkXfermode_opts inside SK_OPTS_NS.

src/opts/SkNx_sse.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkNx_sse_DEFINED
 #define SkNx_sse_DEFINED
 
 // This file may assume <= SSE2, but must check SK_CPU_SSE_LEVEL for anything more recent.
 
-namespace {  // See SkNx.h
-
-
 template <>
 class SkNf<2, float> {
 public:
     SkNf(const __m128& vec) : fVec(vec) {}
 
     SkNf() {}
     explicit SkNf(float val) : fVec(_mm_set1_ps(val)) {}
     static SkNf Load(const float vals[2]) {
         return _mm_castsi128_ps(_mm_loadl_epi64((const __m128i*)vals));
     }
@@ skipping 280 matching lines @@
     }
 
     SkNi thenElse(const SkNi& t, const SkNi& e) const {
         return _mm_or_si128(_mm_and_si128   (fVec, t.fVec),
                             _mm_andnot_si128(fVec, e.fVec));
     }
 
     __m128i fVec;
 };
 
-}  // namespace
-
 #endif//SkNx_sse_DEFINED